The present invention relates to a method for determining the height of textile fiber bales wherein the detacher of a bale opener moves horizontally in succession over the bales of a group of bales and is lowered vertically in the direction toward the bale surface so as to measure the height of the bale in question and wherein an optical proximity switch, for example, is used as the measuring device, the invention also relating to an apparatus for implementing the method.
In a known machine for the automatic removal of material from bales and blending of different fiber types from different bales, e.g. the machine manufactured and sold under the trademark BLENDOMAT by Trutzschler GmbH & Co., Monchengladbach, FRG, it is necessary, before the start of processing, to determine the heights of the individual bales and to feed the resulting height information to an evaluation circuit. This process is performed manually and is therefore subject to subjective influences on the part of the operating personnel. The percentage of each component, or fiber type, in a blended mixture is determined by the number of bales present of that particular fiber type. The height and density of the bales generally vary.
In order to program the desired blend, or mixture, the known BLENDOMAT control is operated manually. The detacher is moved over the highest bale of one type of fiber and is permitted to move downwardly. Once the normal operating height has been reached, an optical proximity switch, or sensor, is activated so that the downward movement is stopped. This height, i.e. the actual height of the detacher, is stored in the memory of the electronic control. Then, according to the required production run, the downward advance, or stroke increment, of the detacher per working cycle is determined. The height of the bale and the stroke increment determine the number of processing runs required to completely process the bales containing this type of fiber. This number is stored as well. Thus, a measurement is made for each bale. Then the detacher is moved to the highest bale of the next type of fiber. The electronic system also stores this value automatically, divides it by the previously determined number of processing runs and stores the required stroke increment for this bale or group of bales, which increment is smaller than that required for the bale or bales containing the first fiber type. The electronic system has a storage capacity for mixtures containing up to four components.
When the processing of all components has been programmed, the control is switched to automatic operation. Then, the detacher is lowered further automatically with each working cycle according to the rate of downward advance programmed for each component or fiber type. Thus, in the prior art process, the height of each bale is measured only once, thus leading to the possibility of certain inaccuracies resulting at least in part from irregularities of the bale surfaces. It is particularly annoying that each measuring location must be approached manually.
The above-described machine is described in greater detail in a brochure entitled "Blendomat BDT Programmable Bale Opener" by Trutzschler GmbH & Co. Kommanditgesellschaft Textilmaschinenfabrik, D-4050 Monchengladbach 3 (FRG).